Directors & Preceptors
Marcello Pagano, PhD; Professor of Biostatistics. Dr. Pagano's research interests include the epidemiology of HIV infection, especially biostatistical methods for the surveillance of the epidemic, and associated testing methodology. On surveillance methods he has concentrated on modeling the effects of reporting delay; on refining back-calculation methods, including research on how to overcome this method's shortcoming when it comes to its inability to evaluate HIV infection in the recent (last 3 or 4 years) past; on how to handle doubly censored observations; longitudinal, observational studies; and economical methods for making the blood supply safer. Dr. Pagano plays an active role in the teaching program of the Department of Biostatistics having more than thirty years of teaching experience. He has been the primary thesis advisor for many students in addition to serving on many thesis research committees.
Rebecca Betensky, PhD; Professor of Biostatistics. Her research interests are truncated failure time data, interval censored data, sequential analysis, and correlated binary data. A major interest in survival analysis is the testing and adjustment for dependent truncation and censoring mechanisms. A major interest in correlated binary data is the analysis of association in the presence of varying cluster sizes. Dr. Betensky is involved also in collaborative and methodological research motivated by brain tumor and neurology studies. She is involved also in collaborative research in AIDS through the AIDS Clinical Trials Group.
Tianxi Cai, ScD; Professor of Biostatistics. Her current research interests are mainly in the area of biomarker evaluation; model selection and validation; prediction methods; personalized medicine in disease diagnosis, prognosis and treatment; statistical inference with high dimensional data; and survival analysis. In addition to her methdological research, Dr. Cai also collaborates with the I2B2 (Informatics for Integrating Biology and the Bedside) center on developing a scalable informatics framework that will bridge clinical research data and the vast data banks arising from basic science research in order to better understand the genetic bases of complex diseases.
Victor DeGruttola, ScD; Professor of Biostatistics. His research activities focus on developments of statistical methods required for appropriate public health response to the AIDS epidemic. The aspects of the epidemic worked on includes modelling processes of infection, natural history of infection with HIV, and clinical research on AIDS therapies. Current research focusses on methods for relating HIV genetic mutations to resistance to antiretroviral drugs. Also serves as Director for the Adult Statistical & Data Analysis Center at the Harvard School of Public Health.
Wafaie Fawzi, DPH; Associate Professor of Nutrition and Epidemiology. Dr. Fawzi' research focuses on examining the role of nutritional and other factors in the etiology of adverse health outcomes among populations in developing countries, with emphasis on infectious and perinatal outcomes among mothers and children. Dr. Fawzi and collaborators are implementing several large randomized controlled trials to examine the efficacy of various micronutrient supplements on the incidence and severity of a number of infectious diseases including pneumonia, diarrhea, tuberculosis, and HIV infection. In collaboration with colleagues at Muhimbili University in Dar es Salaam, Tanzania, the team completed a trial that documented a significant beneficial effect of periodic vitamin A supplementation on child mortality. In another large clinical trial prenatal multivitamin supplementation of HIV-infected women resulted in large and significant reductions in the risk of fetal loss, low birth weight, and severe prematurity. Currently, the group is examining whether the latter findings are generalizable to the larger population of HIV-negative women. As part of the HIV Prevention Trials Network at NIH the team is engaged in examining strategies for reducing perinatal and heterosexual transmission of infection.
Rebecca Gelman, PhD; Associate Professor of Biostatistics at HSPH and Harvard Medical School. She is involved in collaborative research on cancer, AIDS, and general immunology. Is the PI of the biostatistics core of the Harvard Center for AIDS Research, works on the Immunology Committees of the Adult and Pediatric AIDS Clinical Trials Groups, and is the only statistician on the Flow Advisory Committee of the NIAID. Is also coordinator of biostatistics collaboration of the Dana Farber/Harvard Cancer Center (which includes work on AIDs-related malignancies).
Sebastien Haneuse, PhD; Assistant Professor of Biostatistics at HSPH. His methodologic research follows two general themes, the first of which focuses on the development of novel study designs that help address bias encountered in the analysis of data from observational studies. He looks to augment the data collection process with supplementary information that can then be used to directly address the various biases. The simultaneous development of statistical tools that ensure valid and efficient estimation and inference is a crucial aspect of this research. The second general theme of his research involves the development and use of flexible, so-called non- parametric, prior distributions for semi-parametric Bayesian analyses. Two key components of this research are (i) exploiting the flexibility of these specifications to gain additional insights into mechanisms and/or etiology, and (ii) overcoming the consequences of model misspecification, particularly in the analysis of correlated or longitudinal data.
Michael Hughes, PhD; Professor of Biostatistics and Director of the Statistical and Data Management Center for the AIDS Clinical Trials Group. His research involves a variety of issues concerning HIV, with particular emphasis on statistical methods for the design and analysis of HIV clinical trials. One area concerns methhods for the design and analysis of phase I/II studies for "special populations" such as infants, children and pregnant women. Such studies require novel dose-finding methods involving multiple outcome measures, including pharmacokinetic, anti-HIV activity and toxicity outcomes, and complexities related to long-term outcomes. More generally, this area extends to the design and analysis of bridging studies that allow translation of results from large clinical trials in one population to a second population (e.g. from the U.S. to sub-Saharan Africa). Another area of interest concerns the development of semi-parametric methods for longitudinal data analysis including informative missingness and censoring (as with repeated measurements of HIV RNA). These methods are critical for evaluating virologic and immunologic outcomes, as well as growth and development outcomes in HIV-infected children.
David Hunter, ScD; Professor of Epidemiology and Nutrition. He has conducted studies of risk factors for HIV acqusition in Kenya and Tanzania, and in colloboration with Wafaie Fawzi and members of the Department of Nutrition and Muhimbili Medical Center, studying the relation of nutritional factors in HIV progression and perinatal tranmission.
Nan Laird, PhD; Professor of Biostatistics. Her interests include statistical methods for many medical and public health problems, including clinical trials. She is well known for contributions to missing data problems, longitudinal and repeated measures methods. Much work motivated by AIDS clinical trials data. She has also worked on meta analysis and risk assessment, and has directed many doctoral dissertations, and served on many national committees.
James Robins, MD; Professor of Epidemiology and Biostatistics. His research interests include causal inference for randomized and non-randomized HIV studies, longitudinal studies subject to nonrandom dropout, measurement error models, missing data problems, theoretical aspects of semiparametric models. Dr. Robins' has a strong record of collaboration with students, postdoctoral fellows and other faculty on environmental health related problems. He has supervised several doctoral theses in Biostatistics, served on trainee research committees and supervised several summer projects.
Andrea Rotnitzky, PhD Adjunct Professor of Biostatistics. Dr. Rotnitzky's research interest is focused in developing statistical methods for analyzing studies with missing and censored data, complex designs and for causal inference in observational studies and randomized trials. She has developed a general theory for efficient estimation in models with partially observed data. She has applied this theory to the derivation of efficient estimators in several important models for partially observed data configurations and complex designs that are quite common in AIDS studies. These include: longitudinal studies with attrition, drop-out and/or intermittent non-response, current status data, interval censored data, right censored data, non-compliance in clinical trials, two stage designs with validation substudies, verification bias in studies for the evaluation of diagnostic tests. In addition, she has developed models for estimating the causal effects of dynamic treatement regimes from longitudinal observational studies.
George Seage, ScD, MPH; Associate Professor of Epidemiology. Dr. Seage's research involves identifying the biological and behavioral determinants associated with HIV transmission, and to develop and evaluate prevention interventions. One area has been the evaluation of the role of specific drugs, immune response and the impact of antiretrovirals as potential effect modifiers on the sexual transmission of HIV. Another area of interest is the design of interventions to evaluate the impact of preventative HIV vaccines on infection, disease progression and secondary transmission. Another area of interest is the development of methods to estimate the effect of HIV treatments on clinical outcomes using observational designs.
Lee-Jen Wei, PhD; Professor of Biostatistics. His research is in the area of developing statistical methods for the design and analysis of clinical trials. He has developed numerous methods for analyzing data with multiple outcome or repeated measurements obtained from study subjects. In particular, his "multivariate Cox procedures" to handle multiple event times have become quite popular. His work with colleagues led to the development of alternative models to the Cox proportional hazards model for analyzing survival observations. He is also a senior statistician at the Statistical and Data Analysis Center, and works closely with the medical investigators in Pediatric AIDS clinical trials for evaluating new treatments for HIV patients.
Paige Williams, PhD; Lecturer on Biostatistics. Dr. Williams' research is divided between development of statistical methods for AIDS clinical trials and environmental risk assessment. In the area of AIDS clinical trials, she has addressed statistical issues in the design, analysis, and sequential monitoring of trials conducted by the National AIDS Clinical Trial Group (ACTG) for prevention and treatment of opportunistic infections in HIV-infected patients. She was the Head of the Complications of HIV Section of Harvard's Center for Biostatistics in AIDS Research (CBAR) from 1995-1997, and continues to serve as the senior statistician on a number of related clinical trials. Along with these collaborative activities, Dr. Williams has developed statistical methods for monitoring clinical trials with multiple survival endpoints, and has investigated the use of both CD4 and HIV viral load as predictors of the risk of opportunistic infections.